1. Field of the Invention
This invention relates in general to a universal television decoder, and more particularly, to a universal decoder consisting of modules which provide automatic frequency changes and system control of the transmitter and receiver of the decoder by the host computer.
2. Description of Related Art
CATV and satellite systems have been in use for quite some time. However, until now, the television decoders have not been standardized or interchangeably designed.
All the major manufacturers of decoders produce and sell decoders designed specifically for use with their own scramble system. These decoders are equipped with descramblers that can only function in a specific environment. Thus, with different firms producing different coders with different standards, the question of compatibility arises and the need to establish an international standard for decoders becomes evident.
In addition, the development and progress of computers and electronics technologies has brought about more sophisticated scramble systems. Nevertheless, this has given rise to security problems as a result of providing those with ulterior motives more and better tools. Up to now, if there is signal invasion and/or interference from outside to the data communication line between the cable station's host computer and a subscriber set-top unit during normal two-way cable TV operations, the data communication becomes paralyzed because data cannot be transmitted or received.
Specifically, if there are continuous reciprocal interferences and cable station cannot find the signal invasion point, then cable station must collect the set-top unit from every subscriber and physically change the existing data communication frequency from the unit to an uninterfered new frequency. Thus, in the event of security breaches, CATV operators are forced to change not only the scramble system, but all the decoder boxes as well. This creates many problems for the operation of two-way cable TV data communications. Furthermore, this adds on tremendous extra replacement costs that the CATV operator cannot avoid.
Another problem exists with communication between the CATV operator and each subscriber's decoder. Two-way data communication technology is one of the core technologies needed to operate a two-way cable TV system between the CATV operator and the subscriber's decoder. But each decoder manufacturer produces products built specifically for use within their own data communication system. Thus, the question of compatibility arises again. Existing converters do not provide a solution to the signal interference or signal ingress problem during two-way communication between the station and the subscriber converter. Furthermore, due to the technical circumstances, broadcast stations have always used telephone lines for upstream communication. However, because of the telephone modem's disadvantages, it was never possible for perfect two-way communication.
In addition, since existing converter communication methods between the station and the subscriber relied on cable, the converter's communication frequencies were set. Moreover, since each station used different frequencies, there was no compatibility among the converters. In addition, the repair cost is high and the lifetime of the converter is short because the existing converters are made as a single-bodied unit rather than combined modules.
Furthermore, current converter/decoders do not provide international compatibility. For example, video standards differ from country to country, region to region, as does the bilingual and stereo system, the electrical voltage, current cycle, and the frequency apportionment for CATV. It is no wonder that in this situation there isn't a decoder that is compatible with all these various standards around the world. Further, there is no compatibility among parts.
Still further, as new scramble systems are developed around the world, each decoder manufacturer stubbornly clings to their own scramble systems. This strategy does not allow cable operators much choice. Thus, cable operators are forced to choose from one of the few scramble systems decoder manufacturers offer.
For cable TV broadcasting network operation, the traditional two-way data communication system involves a station's host computer calling a subscriber set-top unit using a successive call method. For the subscriber set-top unit to report the data to the host computer, the successive call method took about 30 minutes per 100,000 subscribers. Therefore, the successive call method prohibits performing an instant viewer rating survey for 15 second, 20 second or 30 second short commercials.
Finally, the features that the various decoder manufacturers provide are similar: on-screen display, timer, favorite channel programming, self-diagnostics to name a few. But again there is no compatibility in software menu.
Therefore, it can be seen that there is a need for the development of an internationally compatible universal decoder.
It can be seen that there is a need to improve the lifetime of the converters to semi-permanent to reduce the operation cost of a broadcasting station.
It can therefore be seen that there is a need to improve the traditional two-way data communication system of the cable TV operation so that viewer rating for the short video materials can be precisely surveyed.
It can seen then that there is a need for a universal decoder that has enhanced security features.
It can also be seen that there is a need for a universal decoder which allows remote modifications of frequencies.
It can also be seen that there is a need for a universal decoder which provides greater scramble selection flexibility.